Motor graders are used primarily as a finishing tool to sculpt a surface of a construction site to a final shape and contour. Typically, motor graders include many hand-operated controls to steer the wheels of the grader, position a blade, and articulate the front frame of the grader. The blade is adjustably mounted to the front frame to move relatively small quantities of earth from side to side. In addition, the articulation of the front frame is adjusted by rotating the front frame of the grader relative to the rear frame of the grader.
To produce a final surface contour, the blade and the frame may be adjusted to many different positions. Positioning the blade of a motor grader is a complex and time-consuming task. Frequently, an operator will desire one or more unique blade positions. However, due to the geometry of the motor grader, some adjustments of the blade position may lead to collisions of the blade with parts of the motor grader or unwanted contact with the ground. Such collisions may damage the blade, motor grader, or both. Furthermore, any unwanted contact with the ground may produce unwanted surface shapes and contours that may need to be corrected.
U.S. Pat. No. 6,028,524 issued to Hartman et al. (Hartman) on Feb. 22, 2000 discloses a motor grader, which includes a system for preventing the blade from contacting the front frame and/or the tires of the motor grader. The system in Hartman includes an electronic controller, blade controls having position sensors, and frame controls having position sensors. The controller monitors the output of the position sensors to ascertain the position of the blade and frame controls. When the blade and frame controls receive input signals requesting a repositioning of the blade or frame, the controller determines the present positions of the blade and frame. The controller then calculates future blade and frame positions based on the repositioning request. After calculating the future blade and frame positions, the controller predicts whether an intersection of the future blade position and future frame position will occur. If an intersection of positions is imminent, the controller will either produce a warning signal to the operator or cancel the repositioning request.
Although the system in Hartman may prevent the blade from colliding with the front frame and/or tires of the motor grader, the operator is still left to determine an alternate path for the blade to reach the desired position. Due to the complex geometry of the terrain and motor grader, safely repositioning the blade may be a prohibitively difficult and time consuming task for an operator to perform. Furthermore, planning a new blade path may place such a demand on the operator, that other tasks necessary for the operation of the motor grader may be neglected.
The disclosed system is directed to overcoming one or more of the problems set forth above.